Carbon−Carbon Bond Formation by Electrophilic Addition at the Central Carbon of the μ-η3-Allenyl/Propargyl Ligand on the Pd−Pd Bond

• Published in: Journal of the American Chemical Society 2001-04, Vol.123 (14), p.3223-3228
• Main Authors: Ogoshi, Sensuke, Nishida, Takuma, Tsutsumi, Ken, Ooi, Motohiro, Shinagawa, Tsutomu, Akasaka, Tenpei, Yamane, Mariko, Kurosawa, Hideo
• Format: Article
• Language: English
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/ja003754m

The μ-η3-allenyl/propargyldipalladium complexes were synthesized by the reaction of the corresponding η1-allenyl- or η1-propargylpalladium complexes with Pd2(dba)3. The X-ray diffraction analysis indicates that the dinuclear complex has a unique structure, in which two palladium, three carbon, two phosphorus, and one halogen atoms are in the same plane. These dinuclear complexes react with electrophiles, such as HCl or AcCl, at the central carbon of the μ-η3-allenyl/propargyl ligand to give the μ-η3-vinylcarbenedipalladium complexes. Intramolecular reaction proceeded smoothly to give cyclization products quantitatively. Addition of a catalytic amount of a palladium(0) complex dramatically accelerated the carbon−carbon bond formation. The MO calculations on the μ-η3-allenyl/propargyl complexes indicated that the reaction proceeds via orbital control.